Expand and combine like terms. $(6y^2+5y^4)^2=$
Explanation: We can expand this expression using the "perfect square" pattern (where $P$ and $Q$ can be any monomial): $(P+Q)^2=P^2+2PQ+Q^2$ $\begin{aligned} &\phantom{=}\left(6y^2+5y^4\right)^2 \\\\ &=\left(6y^2\right)^2+2\left(6y^2\right)\left(5y^4\right)+\left(5y^4\right)^2 \\\\ &=36y^4+60y^6+25y^8 \\\\ &=25y^8+60y^6+36y^4 \end{aligned}$